1. Technical Field
The present invention relates to a facsimile device utilizing a process unit for an electrophotographic image recording device, and more specifically, a facsimile device where a drum unit and a development unit are separately structured to be combined as a process unit in use and the process unit is removable as a whole from the facsimile device body. In addition, the present invention specifically relates to a facsimile device having an electrophotographic image recording device where its scan part frame for accommodating a scanner is provided such that it can rotate around a fulcrum axis located along one side of the facsimile body and thus can expose a body frame for accommodating a recording part and a paper feeding part and where the process unit provided in the body frame can be removed/attached by opening an intermediate cover provided at the upper portion of the body frame.
2. Background Art
Conventionally, a process unit integrally constituted of a photosensitive drum, a charger, a development device and the like is used in an electrophotographic image recording device. The processing unit can be designed such that it can be removed from/attached to the facsimile main body. In a facsimile device having such an integrally constructed process unit, if the unit is designed as to be capable of making, say, ten thousand photocopies, information about when the unit to be exchanged and the like is output by assuming the remained life length of the unit according to the number of produced photocopies counted by a counter or the like provided in the image recording device. As a result, when such a process unit is used, no special attention needs to be paid for finding out the life length of the currently used photosensitive drum and the development device and the process unit is to be replaced only when the display of the facsimile main body outputs a replacement command.
In addition, a type of a facsimile device is also available in which means for scanning a document set on a platen glass (FBS: flat bed scanner) and an automatic document feeder (ADF) are both provided. This type of a facsimile device capable of such two document scanning methods has an advantage that it can both perform 1) feeding and scanning a sheet-shaped document by using ADF and transmitting the scanned image signals or 2) scanning a book-shaped document by using FBS and transmitting the scanned image data as desired.
As for the recording part provided in the facsimile device, in addition to the conventional thermosensitive paper and ink donor film method, an electrophotographic method (device) is now available. The electrophotographic recording part, when used in a facsimile device, has an advantage that it brings more excellent image quality of copies and easier and better handling/preservation of those copies.
As mentioned above, the photosensitive drum and the development device arranged in the process unit have to be replaced with new ones when each is exhausted. However, it is not desirable to replace the photosensitive drum and the development device all together because the life length is different in each component (the drum, the development device or the like) and replacing the components all together would waste some of the components that are still alive. Therefore, in some facsimile devices, the photosensitive drum unit and the development unit are separately designed such that each unit can be separately replaced according to the life length of each unit.
However, if the two (photosensitive drum and the development device) units are arranged such that they are to be separately removed/attached, a new problem arises because the unit removal/attachment work becomes troublesome when they have to be xe2x80x9cseparatelyxe2x80x9d removed from the main body due to jammed paper or the like, even though wasting still usable components can be avoided. In addition, the conventional two separate units may cause another problem when each unit is aligned against each other and the image recording device. Therefore, an improved process unit of which removal/attachment is easy has been desired.
Further, when an electrophotographic recording part is provided in a facsimile device, that may result in an increased size of the whole device. In contrast, facsimile devices using the thermosensitive paper or ink donor film can be made small. Therefore, in a facsimile device using a conventional electrophotographic process unit, the device is generally designed as a device of relatively large size combined with a digital electrophotographic copying machines, as is the conventional electrophotographic copying machines. However, needless to say, a smaller-size machine having simpler layout and less maintenance requirements is also demanded in such facsimile devices having an electrophotographic process unit as in other facsimile devices.
Some conventional devices have attempted to solve the problems described above. For example, an invention discloses a combination of separately made drum unit and development unit that can integrally engaged with each other. However, the invention provides no disclosure about how accurate alignment can be achieved when each unit is integrally assembled.
Another invention mentions to an intermediate cover provided in the main frame surface (under a scan unit) that can open/close for removal of these units. However, the cover is rigidly attached to the frame surface with vises in this case and cannot be easily opened/closed if the scan unit is removed. That is, there is no prior art in which such an intermediate cover and a scan part frame can each make separate and free movement.
The present invention is to solve the aforementioned problems associated with the prior art. That is, one object of the present invention is to offer a facsimile device in which engagement means is provided in each of a photosensitive drum unit and a development unit such that they can be separatably engaged with each other by way of the engagement means. As a result, each unit can be separately replaced when it is exhausted without wasting the other. Also, the combined two units can be as a whole thus easily removed from/attached to a facsimile main body.
Another object of the present invention is to provide a smaller electrophotographic facsimile device that allows easier opening/closure of a scan part frame or the like placed on the main body as well as easier maintenance of the process unit in the main body and easier processing of paper.
The present invention relates to an image recording device in which toner image is electrophotographically formed on a photosensitive drum and the toner image is transferred to a paper for making a photocopy.
As a first aspect of the present invention, the photosensitive unit and the development unit are separately designed and removal/attachment means is provided in each of the two units such that they can be separatably engaged with each other. Accordingly, the photosensitive unit and the development unit can be separately replaced depending on life length when either of them is exhausted but can as a whole be removed from/attached to the facsimile main body when removal of jammed paper or the like is to be carried out.
As a second aspect of the present invention, a pair of support bodies projects from the development unit side to the photosensitive drum unit and a drum shaft end portion and a pin member are each provided on each side of the photosensitive unit (the pin member is provided vertically above the drum shaft end portion with a predetermined distance between them). Each pair of the drum shaft end portions and the pin members is arranged in the width direction. The drum shaft end portion and the pin member on each side are each engaged with an associated engagement groove provided on each support body such that the photosensitive unit can be aligned against the development unit. Due to this arrangement (the connection of the drum shaft and the pin member with the engagement groove on each support body), the two units can be integrally assembled.
As a third aspect of the present invention, a holding member capable of resiliently changing its shape corresponding to the insertion of the drum shaft and the pin member of the photosensitive unit is provided on each engagement groove formed at each support body of the development unit. As a result, since this resiliently bendable holding member pushingly holds the pin member of the photosensitive unit on each side, the photosensitive unit is prevented from floating up and also its attachment state can be confirmed with just a glance of an operator.
As a fourth aspect of the present invention, a main body frame having an electrophotographic recording part is arranged separately from a scan part frame having two-way scanning parts (one way is scanning a document fixedly placed on a platen and the other way is scanning a moving document). The scan part frame is placed right on the main body frame such that the scan part frame can be rotated around a fulcrum axis along a side of the main body frame. In addition, an intermediate cover that can open/close in the same direction as the scan part frame does is provided in the main body frame.
Due to this arrangement, the size of the whole device can be made small in the present invention. Also, due to the provision of the intermediate cover for removal/attachment of the process unit of the main body frame, the (electrophotographic) recording part arranged in the main body frame can be protected without being influenced by the operation of the scanning member and the like provided in the scan part frame. In addition, maintenance of the whole device becomes significantly easier by this separate arrangement of the scanning part and the recording part in different frames.
As a fifth aspect of the present invention, the electrophotographic process unit is arranged in the main body frame such that it can be vertically moved for removal/attachment when the intermediate cover is opened. In addition, the process unit is fixedly held at its standard operational position when the intermediate cover is closed. Since the process unit can be accurately aligned and held at the position in the main body frame by the intermediate cover, it is not subjected to any undesirable influence from the opening/closing operation of the scan part frame arranged above it.
As a sixth aspect of the present invention, a platen for loading a document is provided on the upper surface of the scan part frame, and an upper open/close frame having in its upper portion a document feed tray and a document discharge tray corresponding to the automatic document feeder is provided on the upper surface of the platen. More specifically, the upper open/close frame is provided such that it can rotate in the direction perpendicular to the opening/closing direction of the scan part frame (but the fulcrum axis must be horizontal), and the automatic document feeder is also provided on the upper open/close frame (on the fulcrum axis side of the scan part frame) such that a document is fed from the document feed tray to the document discharge tray through the automatic document feeder with making a U-turn in the feeder. Further, the members (mechanism) such as the trays and the automatic document feeder are each integrally provided in the upper open/close frame such that they do not undesirably project from the scan part frame. Yet further, the upper open/close frame is prevented from making any unwanted movements when the scan part frame is opened/closed.